1. Field
This invention relates generally to valved manifold devices, and is specifically directed to such devices in medical conduit systems. It provides a valved manifold particularly useful at the patient intubation interface of endotracheal ventilation/aspiration systems.
2. State of the Art
Many gas delivery systems, particularly in a hospital or laboratory environment, utilize manifold devices for directing fluid flow. There is a variety of circumstances in which it is necessary or desirable to provide multiple, yet isolated, other path ways through the interior of such a manifold. The manifold is often associated with other components as a system. When the individual components of such a system are subjected to mechanical forces tending to rotate one component with respect to another, it is often essential to provide that travel path through a joint structure which permits rotating or swiveling movement.
As an example, closed systems for endotracheal suctioning and ventilating typically include a manifold enabling introduction of ventilating gases and intermittent exhalation of patient breath simultaneously with insertion and operation of a tracheal suctioning catheter. The manifold structure typically includes multiple ports, usually the open ends of respective conduits extending from a common chamber. One such port is interfaced to a patient through a patient connection device. The suction catheter is often included within an assembly which is connectable to a second port of the manifold. The catheter assembly conventionally includes a collapsible plastic envelope positioned to entirely surround the catheter. A practitioner manually externally collapses the envelope onto the external surface of the catheter, and advances the catheter through the manifold into an access tube connected to a patient, retracting the catheter in a similar fashion following the aspiration procedure.
The manifold thus provides a first pathway for ventilation gases, and a second pathway for the catheter. The catheter provides isolation from the ventilating gases for fluids withdrawn from the patient through the manifold. When the catheter is withdrawn, it is often desired to continue regulated ventilation through the manifold. In some cases, it is desirable for the catheter assembly to be disconnected from the manifold, without disturbing the ventilation of the patient. It is thus necessary to provide for a gas tight sealing of the pathway formerly occupied by the catheter upon its removal. Previous efforts in this connection have involved the provision of auxiliary sealing structures for use in association with the manifold. These arrangements have had several disadvantages. Because they have not been integral with the manifold, their use has been inconvenient in practice. With ventilation ports substantially transverse patient interface ports, air turbulence has been disruptive to potentially delicate and fragile ventilation flow. Certain resilient seals have been unacceptable because they lack the positive sealing characteristics of a mechanical valve. Available valves are not suitable for incorporation into a manifold because they lack the essential capability of providing a travel path for a catheter when catheter suction is needed. Any sealing arrangement employed should be as inexpensive as possible, thereby eliminating complex mechanical valve assemblies from practical consideration.
Material prior art structures and methods are described, among other places, in U.S. Pat. No. 5,333,607 to Kee, et. al.; U.S. Pat. No. 5,354,267 to Niermann, et. al.; U.S. Pat. Nos. 5,357,946 and 5,445,141 to Kee, et. al.; U.S. Pat. Nos. 5,140,983 and 5,487,381 to Jinotti; U.S. Pat. No. 5,882,348 to Winterton et al.; U.S. Pat. Nos. 5,735,271 and 5,730,123 to Lorenzen et al. and U.S. Pat. No. 5,642,726 to Owens et al. These patents each disclose ventilator manifold devices and systems in which those devices are utilized. The ""267 patent, for example, discloses a manifold and a multi-position stop cock valve. The valve is provided with a xe2x80x9cTeexe2x80x9d shaped internal stem channel pattern so that the stem may be positioned selectively to wash the internal lumen of a catheter, to irrigate the patient or to accommodate travel of the catheter through the stem to suction the patient. The valve may be plugged directly into an access port of the manifold. Patient ventilation is conducted without respect to the valve through other ports of the manifold. The valve itself constitutes an integral component of a catheter assembly, and must be removed from the manifold with the remainder of that assembly. The ""348 patent discloses a valved manifold embodying a multi-position stop cock valve. The ventilation port is transverse the patient interface port, and is thus characterized by more dead air space than is generally regarded as acceptable for neonatal applications.
A neonatal closed system suction catheter assembly of Alcove Medical, Inc. of Salt Lake City, Utah, Bird Products Corporation of Palm Springs, Calif., and Corpak, Inc. of Wheeling, Ill. includes a depth-finding feature comprising a ring snugly but slidingly surrounding a suction catheter within a collapsible plastic envelope that carries the catheter. After the catheter is advanced to the desired depth, the ring is moved to a point immediately adjacent the manifold. This feature enables a respiratory care practitioner to establish a limit upon the depth to which a suction catheter is insertable into a patient. Accordingly, optimal placement of the catheter tip, once established, need not be reestablished when the catheter is withdrawn and subsequently reinserted. In practice, however, manipulation of the ring from outside the envelope is insufficiently facile.
There remains a need for an inexpensive, yet reliable, manifold assembly incorporating a valve positioned to minimize dead air space within the manifold and capable of passing a catheter. The valve must provide a sealed gas flow path through the manifold in both its open and closed conditions with respect to catheter travel. The manifold should further be removable from any associated catheter assembly. Ideally, the manifold should also include a ventilation port that is substantially axially aligned with the patient interface port. Particularly in neonatal applications, there remains a need for a manifold constructed to minimize fluid flow turbulence of ventilating gases and to minimize the likelihood of respiratory therapy fluids introduced through an aspiration portion of a device from back-washing into a ventilation portion of the device.
A further need remains for a patient ventilation/aspiration system wherein the desired depth of successive insertions of the suction catheter can be established by a single initial procedure by means that are external to the collapsible plastic envelope.
The invention may be embodied as a multi-function manifold positioned at the distal end of a catheter assembly. A catheter tube is slidable lengthwise through a passageway, which includes a first (distal) port at the distal side of the manifold and a second (proximal) port near the proximal side of the manifold. The distal and proximal ports are generally not in alignment. Accordingly, the catheter should be sufficiently flexible to accommodate a bend as it travels through the passageway. A special valve is positioned along the passageway in axial alignment with the distal side, thereby to minimize dead air space and ventilation turbulence. This valve may be operated to open a travel path for the catheter through the manifold. The manifold preferably includes a patient connection conduit at its distal side for attachment to (and communication with) an indwelling intubation device, such as a tracheal tube, endotracheal tube or nasopharyngeal tube. The manifold also includes a ventilating structure extending transversely from (and in fluid communication with) the distal end and the passageway. The ventilating structure constitutes means for selectively introducing ambient air, oxygenated air and other therapeutic gasses into the respiratory system of the patient. Other conduits may also be provided for the introduction of therapeutic and diagnostic implements and for the introduction of other suitable gases and lavage, surfactant and oxygenation solutions to the respiratory system.
The manifold, and in particular, the manifold valve, is structured and arranged to enable simultaneous patient ventilation and protected tracheal suctioning. A suctioning catheter may be coupled at its proximal end to a suctioning valve. The distal end of the catheter may then be fed through a conduit near the proximal side of the manifold for reciprocal movement through the intubation device. The catheter is often provided in an assembly, whereby it is enveloped by a protective barrier that enhances and preserves cleanliness, which is coupled to an access structure near the proximal side of the manifold. The manifold and valve may be integral with the catheter assembly, but are preferably detachable to facilitate multiple uses of the manifold, either in association with other assemblies or for other applications.
The manifold valve is structured and arranged as a stopcock with a specialized valve stem. The valve stem is fashioned to provide the previously described versatility of function to the manifold. The manifold may thus be positioned in a patient ventilating circuit in conventional fashion to function as a portion of that circuit. In that circumstance, the valve stem is positioned to maintain a first, ventilating, flow path through the manifold, including through a portion of the stem. As so positioned, the stem blocks flow through other selected travel paths within the manifold. In particular, the passageway required for the catheter, when it is present, is sealed against gas flow by the stem. The stem may be repositioned to permit passage of a catheter through a slot in the stem, while still maintaining the ventilation flow path in open condition.
A preferred valved manifold assembly includes a stopcock valve with a hollow stem and a transverse slot arranged to permit the stem to be rotated between open and closed positions. In both positions, a substantially axially-aligned ventilating fluid flow pathway is maintained through the stem between ventilator and patient connection ports of the manifold. In open position, the stem provides a travel pathway for a catheter between the patient connection port and an access port of the manifold. In closed condition, the stem seals this travel pathway. This structure is ideally suited for inclusion in patient ventilation/aspiration systems which would benefit from less dead air space and less turbulence in the flow of ventilation gas.
In summary, an interface assembly for closed system endotracheal ventilating and aspirating procedures may be embodied as a manifold having a proximal manifold end and a distal manifold end. The manifold includes a ventilating port at its proximal end, in open communication with an interior chamber; a patient connection port at its distal end, also in open communication with the interior chamber and further in substantial registration with the ventilation port; and an access port which may be at the proximal end and which is in communication with the interior chamber and substantially out of registration with the patient connection port. Accordingly, a fluid flow path is formed through the interior chamber between the ventilation port and the patient connection port. The access port and patient connection ports are positioned to provide a catheter travel pathway through the access port, the interior chamber and the patient connection port. The catheter travel pathway and fluid flow path in a typical embodiment may be separated throughout the interior chamber between the proximal manifold end and the distal manifold end by a wall. In such an embodiment, an irrigation access tube may be provided in fluid communication with the access port, whereby respiratory therapy fluid may be introduced. This arrangement advantageously enables the introduction of surfactants, oxygenation liquids, saline lavage and other fluids for respiratory therapy without exposing the ventilation circuit and the fluid flow path to such therapeutic fluids.
The assembly further includes a valve comprising a valve stem positioned within the catheter travel pathway. The stem is constructed and arranged for movement between first and second positions. In the first position, the stem blocks the pathway. In the second position, the stem provides a portion of the catheter travel pathway. Actuation structure may be associated with or linked to the stem and manually operable to move the stem between the first and second positions. The valve is further constructed and arranged to avoid blocking gas flow between the ventilation port and the patient connection port.
In a typical embodiment, the access port is oriented generally transverse the patient connection port while the ventilation port is generally axially aligned with the patient connection port. The valve stem is ideally positioned within the interior chamber and is structured with a hollow center cavity opening towards the ventilation port. The hollow center is in open communication with the patient connection port, typically by means of a slot transverse the cavity and in registration with the patient connection port when the stem is in either the first or second positions. The stem includes a wall with an outer surface in sealing relationship with the access port when the stem is in the first position. An opening through the wall into the cavity is positioned and configured to register with the access port when the stem is in the second position.
In use, the manifold assembly is interposed between an indwelling tube at the distal end of the manifold and a ventilating circuit at the proximal end. These junctions may embody a swivel configuration to permit left or right bedside placement of the catheter assembly, and free rotation of the ventilation circuit and patient connection relative to the catheter assembly to reduce the risk of extubation. The apparatus is structured and arranged to permit connection between tubular elements or conduits associated with such components. It is uniquely useful for connecting the manifold of this invention into endotracheal ventilating and aspirating assemblies.
The access port of the interface assembly may be structured and arranged to accommodate axial advancement and retraction of the catheter assembly while maintaining positive end expiratory pressure within the interior chamber. In such an embodiment the catheter assembly may include a suction catheter with a proximal end, a distal end portion for advancement through the access port and a clip associated with the suction catheter. The clip is selectively located at a point that defines the transition from the distal end portion and the proximal end and, thus, the proximal end is prevented from being advanced beyond the access point. In a preferred embodiment, a flexible sheath carries and substantially envelopes the suction catheter, and the clip is positioned outside the flexible sheath and is selectively attachable to the catheter through the sheath to selectively define the transition point between the proximal end and the distal end portion. In use, the ideal depth to which to advance the distal end portion of the catheter for a suctioning procedure need only be determined once. In subsequent procedures, the clip serves as a depth marker.